Apr 20th 2012, 8:32 by J.P. | LONDON
HOW many people in the world have bank accounts and what do they use them for? You would think there would be answers to those questions, given that banking is the quintessentially global business, and is important not only in the West but in developing countries, where banks can help poor people save, borrow and invest. Yet, until now, data on the global reach of financial institutions have been limited. The IMF publishes a financial access survey of depositors and borrowers. But there is little about how much people save or why they borrow. Especially little is known about the banking practices of the poor, women and young people. So a big data hole got plugged last year when the Gates Foundation, the World Bank and Gallup World Poll carried out the biggest survey yet of how people save, borrow, make payments and manage risk. The results have just appeared.